Method of preparing stencil emulsions.



J. A. BAILEY & H. E. KALUSOWSKI.

METHOD 0F PREPARING STENCIL EMULSIONS. APPLICATION FILED 1u.NE27, 1916.

1,231,554., Patented July 3, 1917. l

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JAMES A. BAILEY AND HENRY E. KALUSOWSKI, OF WASHINGTON,`DISTABICT OF COLUM- BIA, ASSIGNORS TO ADDEESSOGRAPH CO., OF CHICAGO, ILLINOIS, A CORPORATION' OF ILLINOIS.

METHOD OF PREPARING- STENCIL EMULSIONS.

Specification of Letters Patent.

thisA application iled .Tune 27,

1916. Serial No. 106,289.

To all whom z't may concern:

Be it known that we, JAMES A. Barmer and HENRY E. KALUsowsxl, citizens of the United States of America, and residents of Washington, District of Columbia, have invented a new-and useful Improvement in Methods of Preparing Stencil Emulsions, which invention is fully set forth in the following specification.

The present invention is a division of our application Serial No. 15,557, filed March 19, 1915, for improvements in paper stencils and baths for making the same.

The object of the present invention is to provide an improved method of preparing stencil-sheet emulsions whereby a stencilsheet made in accordance with our process will possess the characteristic property of retaining its susceptibility of taking stencil impressions without requiring the application of moisture to soften the sheet; and will retain the characters impressed therein,

' thereby enabling repeated use of the stencil;

will be ink-resisting; and will enableink solvents to be used in cleaning the stenc1lsheet without injury thereto.

Heretofore stencil-sheets have been made Y for producing multiple copies `by applying to a porous fibrous base, such as Japanese Yoshino paper, a. solutionh of gelatin in water and glycerin, together with a toughenlng agent for the gelatin, such as potassium di-`v chromate. Stencil-sheets have also been made by saturating tissue paper with paraffin or wax. Sheets thus prepared, when impressed by a stylus or by typewriter type characters, are expected to give a stencil through which ink will readily pass at those portions of the sheet so impressed but where the paper has not been impressed, .no ink should pass through the sheet. Gelatin stencil-sheets yield good printing results when the sheet is freshly prepared, or if subsequently moistened, but the tendency of the sheet to dry and harden and to necessitate moistening just before each sheet is used, has proven a serious drawback to the practical use of this form of stencil. The objection $0 the paraffin or wax stencil resides in the susceptibility of the wax soften in summer temperatures and render the charactersl illegible under printing conditions.

- We have discovered that lanolin, a product of wool fat or wool wax., and certain hard waxes mixed therewith, such as paralin, ceresin, or carnauba wax or mixtures,

ratentedauly s, 1era. i

ing bath in the form of an emulsion by maktetrachlorid, C014, a solution of lanolin, preferably anhydrous, ceresin and carnauba wax, alone or mixed, and separatelypreparing a gelatinous solution preferably contain1 ing gelatin, glycerin and water. The two solutions are thoroughly incorporated while warm to form an emulsion, and a toughening agent, such as potassium dichromate, then added. The emulsion is now ready for applying to the fibrous, porous paper, such as Yoshino paper.

The following composition has been found satisfactory and is given by way of example.

Parts are given'by weight:-

l' The bath is prepared 'from the above ingredlents by incorporating them preferably in the following manner. The ceresin, carnauba wax and lanolin are placed in a receptacle, which is preferably adapted to be closed, and the ltemperature raised sufficiently to melt the materials. tetrachlorid is next added to eli'ect a solution. The gelatin is dissolved separately in water and glycerin; themixture is then emulsied' and the potassium dichromate ing with a volatile solvent, such as carbon, v

The carbon are incorporated at a temperature of be- `tween 26 and 33 C. `to form the emulsion.

In the accompanying drawings- Figure 1 isa skeleton diagram setting forth the elements of applicants composition; and

Fig. 2 is a vertical .section through the sheet of paper coated with said composition.

Referring to Fig. 2, 1 is a sheet of paper, and 2v is a coating applied thereto.

. The emulsion or bath may be applied to the porous, fibrous paper, such as Yoshino paper, in various ways, but the preferred way is to float the paper on the surface of the warm bath and remove the excess of liquid by drawing the coated side over a smooth edge, such as a rod supported above the bath. The coated paper is then permitted to yield up -its volatile solvent and excess of moisture in any suitable manner. The sheet is then ready for receiving stencil impressions and is strong and durable. The temperature of the room in which the coating is applied should be sufcient to prevent too rapid setting of the ingredients of the emulsion. A room temperature of about 21 C. is suitable. If a single ply stencil-sheet is desired, as indicated diagrammatically in cross-section in Fig. l, each sheet is permitted to dry separately.

In the preparation of the stencil-sheet, the

' lanolin plays an'important part, both in making the bath and in the completed stencil. Because of the capability of lanolin to combine with water in a marked degree to form an emulsion, and also to blend with the waxes, it materially facilitates in emulsifying the waxes. the minute particles or globules held in the gelatinous matrix consist of a blend of hard wax, and `lanolin which holds water and glycerin. These wax bodies in the gelatin act to'seal the moisture in the coating, while in themselves they have the property of keeping the coating, alive or in a plastic state for receiving stencil impressions without adding moisture to the surface. The

- lanolin also enables the content of glycerin to be increased without rendering the stencil surface sticky. 1

The carnauba wax gives stability to the im ressions under printing conditions, espe- `cia ly when the temperature is elevated, as

in summer.

The emulsion applied to the paper is plastic and is readily displaced by the type of a typewriter leaving a network of bers of the paper through which ink readily penetrates. The surface where the stencil characters are not formed is impervious to, and is practically insoluble in, all forms of ink and most solvents, to which the sheet would be apt to be subjected,

In the finished stencilV The emulsion composition, when applied by the flotation method, has the peculiarproperty of depositing a coating of waxy particles, mainly on the surfacev of the paper, which do not penetrate through or to the opposite side, or to any material extent into ythe body of the paper, but which are retained by a matrix of gelatin on and near the surface.

izing the composition on the surface than by permitting the composition to disseminate through the paper.

When it is desired to 'produce a stencil- It has been found that better -results are attained in stenciling by localsheet of greater strength, it is found preferof interposing between the coating and thel type-characters a protecting layer of fiber which enables the type to present clean faces after prolonged use.

It is to be understood that the proportions given above may be varied within quite wide limits. For instance, to increase the hardness, the carnauba wax may be increasedor even replace the ceresin. Toughness may be varied by varying the proportions of gelatin and potassium dichromate. In lieu of potassium dichromate, other toughening,

agents may be substituted, such as formaldehyde. While we prefer to use and do use a toughening agent, it is to be understood that it may be omitted without sacrificing all the advantages of our invention.

Instead of carbon tetrachlorid, other volatile solvents may be used, such as xylol,"

chloroform, benzin, or the like, but the4 ingredients named in the formula are preferred.

While we have sessing qualities which peculiarly adapt it for use in our process, to wit, the qualities of absorbing water in a marked degree and of facilitating the formation of wax emulsions, we desire it to be understood that We consider other waxes possessing these characteristics as the equivalent of lanolin for the purpose of our invention.

What is claimed is l. TheA method of preparing a stencil emulsion consisting in melting together a hard wax and lanolin dissolving the mixmentioned lanolin as posture in a volatile solvent and emulsifying by absorbing water, dissolving the mixture in a volatile solventI and emulsifying the solution in a solution of gelatin, Water and glycerin to which has been added a toughening agent.

3- The method of preparing a stencil emulsion consisting in forming a solution of al plurality of waxes one of which is characterized by absorbing Water in a volatile solvent and emulsifying the solution by mixing the saine with a gelatin medium.

4. The method .of preparing a stencil emulsion consisting in forming a solution of a plurality of waxes one of which is characterized by absorbing water in a volatile solvent and incorporating therewith an emulsifying agent to form the emulsion.

In testimony Whereoi:` we have signed this specification.

JAMES A. BAILEY. HENRY E. KALUSOWSKI. 

